luckadjusted

Wild Card 2023 · January 13, 2024

Dolphins at Chiefs, Wild Card 2023: who deserved to win?

The Chiefs beat the Dolphins 26–7 and were the better team on the day: replayed with the same form, they win 6 of 10.

Before kickoff the Chiefs were 63% favorites. The biggest swing (Q1, 3:11 left): the Dolphins were stopped on 3rd & 5, worth 12 points of win probability to the Chiefs.

Final

Miami Dolphins 7
Kansas City Chiefs 26

January 13, 2024 · GEHA Field at Arrowhead Stadium · Closing line: Chiefs −4.5

Luck index +38 Chiefs lucky · −38 Dolphins

Each team’s own plays from this game, resampled into new drives 4,000 times: with the way both teams actually played, how often does this performance win? How the replay works

Ten replays. Dolphins win 4, Chiefs win 6.

  1. 1 MIA 29 KC 10
  2. 2 MIA 24 KC 13
  3. 3 MIA 16 KC 10
  4. 4 MIA 23 KC 21
  5. 5 MIA 13 KC 15
  6. 6 MIA 10 KC 14
  7. 7 MIA 7 KC 14
  8. 8 MIA 13 KC 24
  9. 9 MIA 6 KC 20
  10. 10 MIA 7 KC 30

Three other ways to ask

Each answers a different question, so none of them replaces the replay above.

The closing betting line, turned into a probability. What everyone knew before the game.

The line plus what this game showed, weighted by how much one game can tell. It stays close to the line because one game says little.

Every kick, fumble bounce, drop, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.

How 4,000 replays ended

Dolphins win 38% of them, Chiefs 62%, counting the 3% still level after regulation as half each. The line is what actually happened: Chiefs by 19.

Show as a table
Final margin in the replaysShare of replays
Dolphins by 17+6.0%
Dolphins by 9–1612.5%
Dolphins by 1–819.1%
Level after regulation2.9%
Chiefs by 1–828.2%
Chiefs by 9–1616.2%
Chiefs by 17+15.0%

Where the luck was

What the luck was worth

Every lucky and unlucky play, weighted by the moment it happened: its swing in win probability, added up by kind. A missed kick in a decided game counts for nothing; the same kick at the end of a tie game can be most of a win.

Swings add up across a game, so in one that went back and forth they can pass 100%. On the scoreboard the same luck was worth +3.0 points to the Chiefs: the final margin was Chiefs by 19, without the luck Chiefs by 16. Luck shares are the fitted ones (how much of each kind is luck).

The kicks

How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.

  • H. Butker, 28 yds made · 97% expected
  • H. Butker, 26 yds made · 98% expected
  • H. Butker, 32 yds made · 93% expected
  • H. Butker, 21 yds made · 100% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Dolphins 8 for 62 yards, Chiefs 5 for 45 yards

Every accepted flag, in order, and what it did to the helped team’s chance of winning at that moment, including any play it wiped out (points on the scoreboard in grey). A flag in a decided game is worth nothing; one at the turn of a close game can be worth most of a win. Judgment calls count toward luck, pre-snap fouls mostly don’t. How calls are valued

WhenFlagWin probability for
Q1 9:43 False Start on the Dolphins, 5 yards · pre-snap +1% KC +0.9 pts
Q1 3:39 Illegal Formation on the Dolphins, 4 yards · pre-snap +2% KC +1.2 pts
Q2 14:01 Illegal Block Above the Waist on the Chiefs (Cam Jones), 10 yards +1% MIA +0.9 pts
Q2 8:24 Illegal Block Above the Waist on the Chiefs, 10 yards, wiping out the play +11% MIA +3.4 pts
Q2 2:00 False Start on the Dolphins (Tyreek Hill), 5 yards · pre-snap +2% KC +0.3 pts
Q2 1:43 Defensive Holding on the Dolphins (David Long), 5 yards +1% KC +0.3 pts
Q2 1:14 False Start on the Chiefs, 5 yards · pre-snap +1% MIA +0.4 pts
Q2 0:06 Illegal Use of Hands on the Dolphins, 10 yards +2% KC +0.2 pts
Q3 2:24 Roughing the Passer on the Dolphins (Brandon Jones), 15 yards +2% KC +1.4 pts
Q4 15:00 Offensive Holding on the Chiefs, 10 yards +1% MIA +0.9 pts
Q4 13:23 Intentional Grounding on the Chiefs (Patrick Mahomes), 10 yards +1% MIA +1.1 pts
Q4 13:19 Roughing the Passer on the Dolphins (Christian Wilkins), 13 yards +2% KC +2.8 pts
Q4 10:15 Delay of Game on the Dolphins, 5 yards · pre-snap +1% KC +0.6 pts

Dolphins penalties, every game · Chiefs penalties, every game · All teams, 2023

When it happened

Chiefs’ chance of winning

Numbers mark the biggest luck moments, listed below.

nflfastR’s in-game win probability. It ignores the betting line, so it starts near even. Shaded above the middle while the Chiefs were ahead in it, below while the Dolphins were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:49 The Chiefs converted 3rd & 103rd & 4th downs · 30% expected +7% KC KC: Touchdown
2 Q1 3:11 The Dolphins were stopped on 3rd & 53rd & 4th downs · 40% expectedThe Dolphins threw an interception-worthy pass, and it was pickedInterceptions · 48% expected to stay out of the defense's hands +12% KC MIA: Touchdown
3 Q2 10:29 The Chiefs were stopped on 3rd & 13rd & 4th downs · 76% expected +7% MIA KC: Field goal
4 Q2 9:42 The Chiefs converted 4th & 53rd & 4th downs · 43% expected +12% KC KC: Field goal
5 Q2 8:24 Illegal Block Above the Waist on the Chiefs, 10 yards, wiping out the playJudgment calls +11% MIA MIA: Turnover on downs
6 Q2 4:35 The Dolphins were stopped on 4th & 13rd & 4th downs · 72% expected +8% KC MIA: Punt
7 Q2 2:00 The Dolphins were stopped on 3rd & 133rd & 4th downs · 22% expectedFalse Start on the Dolphins (Tyreek Hill), 5 yardsPre-snap flags · 15 flags in 4457 snaps before, position avg 1 per 420 +7% KC MIA: Punt
8 Q2 1:14 The Chiefs converted 3rd & 103rd & 4th downs · 30% expectedFalse Start on the Chiefs, 5 yardsPre-snap flags +7% KC KC: Field goal

Missing players

Key players (usually on the field for half the snaps or more) who missed this game or part of it, valued by position and quality. The same players are missing in every replay, so this counts as luck in points only.

  • Wanya Morris (KC T), out · 0.4 pts
  • Bryan Cook (KC FS), out (IR) · 0.3 pts
  • Skyy Moore (KC WR), out (IR) · 0.2 pts
  • Xavien Howard (MIA CB), out · 1.2 pts
  • Connor Williams (MIA C), out (IR) · 0.6 pts
  • Jevon Holland (MIA SS), out · 0.5 pts
  • Andrew Van Ginkel (MIA LB), out (IR) · 0.4 pts
  • Bradley Chubb (MIA LB), out (IR) · 0.4 pts
  • Jerome Baker (MIA LB), out (IR) · 0.3 pts
  • Jaelan Phillips (MIA LB), out (IR) · 0.3 pts

Adjust the assumptions

Disagree with how much of a fumble bounce or a pass interference call is luck? Change it and the coin-flip replay reruns in your browser.

Only coin-flips re-rolled

Dolphins 0% · Chiefs 100%

Final margin
Chiefs by 19
Luck in points
3.0 for the Chiefs
Luck-adjusted margin
Chiefs by 16.0
Replay with same day's form
Dolphins 38% · Chiefs 62% unchanged: why
How much of each is luck?

0% treats it as skill, 100% as pure luck. The tick is our fit.

What counts

We tested momentum on 19,000 lucky breaks and found none, so it's off by default. Why

Flip a play

Force the other outcome, in this game and in every replay: a made kick becomes a miss, a stop becomes a conversion, a flag goes the other way.

About these numbers

Play-by-play and win probability from nflfastR via nflverse; kicks valued against each kicker’s own record; drops and interception-worthy throws from FTN charting; injuries from snap counts and injury reports.

Methodology and validation · All Wild Card 2023 games · Dolphins · Chiefs

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